C 44 ] 



1 9. Lead is of specific gravity 1 1 352 ; it fuses 

 at a temperature rather higher than tin. The num- 

 ber representing it is 398. 



C 2O. Bismuth is a brittle metal of specific gravity 

 9822. It is nearly as fusible as tin ; when cooled 

 slowly it crystallizes in cubes. The number repre- 

 senting it is 1 35. 



21. Antimony is a metal capable of being volat- 

 ilized by a strong red heat. Its specific gravity is 



6800. It burns when ignited with a faint white light. 

 The number representing it is 1 70. 



22. Arsenic is of a blueish white colour, of 

 specific gravity 8310. It may be procured by heating 

 the powder of common white arsenic of the shops 

 strongly in a Florence flask with oil. The metal rises 

 in vapour, and condenses in the neck of the flask. 

 The number representing it is 90. 



23. Manganesum may be procured from the 

 mineral called manganese, by intensely igniting it in 

 a forge mixed with charcoal powder. It is a metal 

 very difficult of fusion, and very combustible ; its 

 specific gravity is 6850. The number representing it 

 is 177. 



24. Potassium is the lightest known metal, being 

 only of specific gravity 850. It fuses at about 150, 

 and rises in vapour at a heat a little below redness, 

 It is a highly combustible substance, takes fire when 

 thrown upon water, burns with great brilliancy, and 

 the product of its combustion dissolves in the water. 

 The number representing it is 75. It may be made 

 by passing fused caustic vegetable alkali, (the pure kali 



